In recent years, the technology called OpenFlow (OpenFlow) is proposed (refer to Non Patent Literatures 1 and 2). OpenFlow identifies communications as end-to-end flows, and performs path control, failure recovery, load distribution, and optimization on a per-flow basis. An OpenFlow switch specified in Non Patent Literature 2 includes a secure channel for communication with an OpenFlow controller. The OpenFlow switch operates according to a flow table in which appropriate adding or rewriting is instructed by the OpenFlow controller. In the flow table, a set of a matching condition (Match Fields) to be matched against a packet header, flow statistics information (Counters), and instructions (instructions) defining processing content is defined for each flow (refer to section “4.1 Flow Table” in Non Patent Literature 2).
When the OpenFlow switch receives a packet, for example, the OpenFlow switch searches the flow table for an entry having a matching condition that matches header information of the received packet (refer to “4.3 Match Fields” in Non Patent Literature 2). When an entry that matches the received packet is found as a result of the search, the OpenFlow switch updates the flow statistics information (one or more Counters), and executes processing content (i.e., packet handling content, e.g., transmission of the packet from a specified port, flooding of the packet, discarding of the packet, or the like) described in the instruction field of the entry. On the other hand, when the entry that matches the received packet is not found as a result of the search, the OpenFlow switch transmits to the OpenFlow controller a request for setting the entry, or a request (Packet-In message) for transmitting control information for processing the received packet, through the secure channel. The OpenFlow switch receives the flow entry in which the processing content is defined, and then updates the flow table. In this manner, the OpenFlow switch performs packet forwarding by using the entry stored in the flow table as the control information.
Patent Literature 1 discloses an optical network system constituted from means for establishing optical paths, a plurality of optical edge routers configured to connect external IP networks to an optical network, and a plurality of optical cross-connect apparatuses including switching means for each optical path in order to connect the optical edge routers by the optical paths.